GPS Track Simplifier

Cut a GPS track down to the points that carry its shape, with a tolerance you choose in metres.

Track data

<?xml version="1.0" encoding="UTF-8"?>
<gpx version="1.1" creator="Virtual Tools" xmlns="http://www.topografix.com/GPX/1/1">
 <trk><name>Harbour path walk</name><trkseg>
  <trkpt lat="47.659200" lon="-122.405790"/>
  <trkpt lat="47.659210" lon="-122.405603"/>
  <trkpt lat="47.659190" lon="-122.405408"/>
  <trkpt lat="47.659200" lon="-122.405192"/>
  <trkpt lat="47.659210" lon="-122.404997"/>
  <trkpt lat="47.659189" lon="-122.404810"/>
  <trkpt lat="47.659200" lon="-122.404596"/>
  <trkpt lat="47.659210" lon="-122.404393"/>
  <trkpt lat="47.659189" lon="-122.404209"/>
  <trkpt lat="47.659201" lon="-122.404002"/>
  <trkpt lat="47.659210" lon="-122.403790"/>
  <trkpt lat="47.659189" lon="-122.403605"/>
  <trkpt lat="47.659201" lon="-122.403407"/>
  <trkpt lat="47.659342" lon="-122.403405"/>
  <trkpt lat="47.659459" lon="-122.403403"/>
  <trkpt lat="47.659614" lon="-122.403391"/>
  <trkpt lat="47.659738" lon="-122.403407"/>
  <trkpt lat="47.659869" lon="-122.403400"/>
  <trkpt lat="47.660021" lon="-122.403393"/>
  <trkpt lat="47.660135" lon="-122.403409"/>
 </trkseg></trk>
</gpx>

A GPX file, a GeoJSON LineString, or one “latitude, longitude” pair per line. GeoJSON coordinates are in [longitude, latitude] order.

Tolerance

metres: a point is dropped when it lies within this distance of the simplified line

Press Simplify track to reduce the sample route.

Douglas–Peucker simplification keeps the first and last point and drops every point that lies within the tolerance of the line between its neighbours, then repeats on the pieces that are still too far off. Distances are measured on a flat projection centred on the track's mean latitude, which is accurate for a track within one region but drifts for a route spanning continents. A GPX file is read from its trkpt, wpt and rtept elements; a GeoJSON feature, geometry or coordinate array must hold a single LineString. Cutting corners makes the track shorter, and the length, the point reduction and the largest offset of a dropped point are all reported so you can see what the tolerance costs. Everything runs in your browser with no uploads or network access.